Jason, that leaves out most of the Michigan State Parks, as there are only a handful or two of full hookup sites.
BUT if you would consider the electric only hookups and majority of them 30 AMP, - - - - - - - -
Summer camping in Michigan for us IS State parks, load up the water, shower in the shower house, lakes,hiking, biking, fishing, swimming, etc. Some of our fav places are Yankee Springs Rec Area, Gun Lake campground,
Lake Michigan campgrounds, although there are a lot of sites we cannot get into, but, if we can! wahooooo.
Also like Waterloo Rec area campgrounds,
Pontiac Lake State Rec area campgrounds.
Holly Recreation area campground. Near there, have not been to it in years, Seven Lakes.
Used to like Sterling State Park on Lake Erie, until they up and moved the entire campground out on the lake, goodness, we could not stand it out there unless it was hotter than hades, you know, that cold wind off the lake, etc. They do have some full hookups tho, so I have been told.
You could start here:
http://www.michigandnr.com/parksandtrails/Default.aspx?SearchType=campgrounds
Sorry we almost never stay in private/commercial campgrounds in Michigan.
No matter where you stay, be sure to have LOTS O FUN!!